Constraint Imperative Programming

这个项目继续在约束命令式编程（CIP）语言上的工作。约束表示应该由计算机程序维护的关系。约束具有许多理想的属性，这些属性使它们在构建系统（如交互式图形应用程序）时非常有用。它们是声明性语句，而不是命令性语句;程序员只需要陈述“什么”而不是“如何”。在编程语言本身中嵌入对约束的支持带来了额外的优势。首先，程序员使用约束变得很方便。其次，语言实现可以确保自动检查约束。第三，将标准构造表示为约束可以产生更统一和优雅的语言。 最后，为编译器提供了更多的优化机会。 在这个项目中，活动包括研究编译面向对象的约束命令式语言（如Kaleidoscope）的技术，以产生有效的代码。为了做到这一点，系统 尽可能多地对约束进行编译时分析。 其他活动包括开发工具，用于编写，浏览和调试约束命令式程序，调查万花筒程序的编译运行在共享内存MIMD机器上，并通过编程一组代表性的应用程序来测试这类语言的实用性。另一个重要的焦点是开发一个更有效和强大的约束满足算法。最后一项活动是对约束系统的调试支持。约束满足算法和调试方面的工作对于支持约束命令式语言以及其他类型的基于约束的系统都是有用的。

This project continues work on Constraint Imperative Programming (CIP) languages. A constraint represents a relation that should be maintained by a computer program. Constraints have a number of desirable properties that make them useful in building systems such as interactive graphical applications. They are declarative statements, rather than imperative statement; a programmer need only to state ``what'' rather than ``how''. Additional advantages result from embedding support for constraints in the programming language itself. First, it becomes convenient for programmers to use constraints. Second, the language implementation can ensure that the constraints are checked automatically. Third, a more uniform and elegant language can result from expressing standard constructs as constraints. Finally, more opportunities for optimization are opened to the compiler. In this project, the activities include investigating techniques for compiling object-oriented constraint imperative languages, such as Kaleidoscope, to produce efficient code. To accomplish this, the system does as much compile time analysis of the constraints as possible. Other activities include developing tools for writing, browsing, and debugging constraint imperative programs, investigating the compilation of Kaleidoscope programs to run on shared memory MIMD machines, and testing the utility of this class of languages by programming a set of representative applications. Another important focus is the development of a more efficient and powerful constraint satisfaction algorithm. A final activity is work on debugging support for constraint systems. The work on constraint satisfaction algorithms and debugging is useful both to support constraint imperative languages, as well as other kinds of constraint-based systems.